1H NMR Research Articles

The formation of CaCO3-based binder by carbonating high-dosage Ca(OH)2 + slag + NaHCO3 (HCHSN) cement paste

Normally, carbonation can cause the decalcification of C-(A)-S-H gel of alkali-activated cement and the degradation of mechanical properties. While, we propose another possibility to form CaCO3-based binder by carbonating the alkali-activated slag cement of high-dosage Ca(OH)2 (30%) + slag (70%) + NaHCO3 (5.11% by weight of Ca(OH)2 and slag) (HCHSN) in this study. The results supported that the compressive strength and volume stability of HCHSN cement paste can be improved by the carbonation curing and the carbonated HCHSN cement paste could reach a maximum compressive strength of 32.4MPa. According to the micro-analysis of XRD, TGA, FTIR, 1H NMR, BSE and SEM, the carbonated HCHSN cement paste was developed into a CaCO3-based binder with a CaCO3 content approaching 60% (based on the mass of the samples heated to 800℃). NaHCO3 played a key role in the formation of the CaCO3-based binder, which not only accelerated the carbonation rate, but also promoted the carbonation of slag. The eco-efficiency assessment showed that compared to the production of 12.5kg CO2 /MPa/t from carbonated ordinary Portland cement, the carbonated HCHSN cement paste only produced 3.5kg CO2 /MPa/t, making it a very green CaCO3-based cementitious materials.

Synthesis of potential anticonvulsants based on chloral hydrate and carbamazepine: their spectral characteristics and in silico ADME profiling

This paper reports the synthesis of a new potential anticonvulsant, N-(2,2,2-trichloro-1-hydroxyethyl)-5H-dibenzo[b,f]azepine-5-carboxamide. Its synthesis is based on condensing the anticonvulsant drug carbamazepine with chloral hydrate used in medical practice. The reaction was carried out in a melt or by boiling in dry benzene with the removal of the resulting water from the reaction medium. The product was obtained with yields of 88 and 79%, respectively. Replacing the hydroxyl group in the resulting condensation product with an amino group led to the formation of N-(1-amino-2,2,2-trichloroethyl)-5H-dibenzo[b,f]azepine-5-carboxamide. This synthesis was carried out in two stages. Initially, the hydroxy derivative was chlorinated with thionyl chloride. Then, by treating the resulting chlorine derivative with an aqueous solution of ammonia (25%) in MTBE medium, the target product was obtained. The structure of the obtained compounds was proven by 1H NMR and IR spectroscopy data. The SwissADME online platform showed that the synthesized compounds should have high bioavailability as well as moderate solubility in water and be able to penetrate the blood-brain barrier.

Novel Benzohydrazide Derivative as a Potential Anticarcinogenic Agent for Breast Cancer: Synthesis, Crystal Structure, In Vitro and In Silico Assessments

Polycyclic aromatic compounds (PACs) are a class of organic molecules known for their significant biological activity, including anticancer properties. These compounds often interact with biological macromolecules, making them crucial in the development of new therapeutic agents. In this study, we report a new benzohydrazide derivative, (E)-4-(hexyloxy)-N'-(1-(naphthalen-2-yl)ethylidene)benzohydrazide (2), which incorporates a naphthalene ring, a typical PAC, as a core structural element. The structure of the compound was analyzed using FTIR, 1H NMR, 13C NMR and elemental analysis. Moreover, single crystal X-ray crystallography studies demonstrated that the compound adapted monoclinic crystal system with C 2/c space group. In the crystal structure, the intermolecular N–H···O hydrogen bonds link the molecules into infinite chains along the b-axis direction. The dominant interactions formed in the crystal packing were found to be hydrogen bonding and van der Waals interactions according to the Hirshfeld surface (HS) analysis. The evaluation of energy frameworks showed that stabilization of the compound was dominated by dispersion energy contribution. The anticancer activity of the compound was tested by employing several cellular assays. The compound showed strong anticancer effects, with IC50 values of 85 µM for MCF7 cells and 115 µM for MDA-MB-231 cells, indicating dose-dependent suppression of cell viability, migration, and colony formation. Computational analyses indicated favorable binding of compound 2 to ERRγ and predicted good oral availability of the generated compound. Pathway analysis using KEGG pathways identified significant enrichment in pathways related to cancer. These results highlight the compound's promise as a potential treatment option for breast cancer, prompting further exploration in future studies.

Bioavailability Improvement by Atomic Layer Coating: Fenofibrate A Case Study

Biopharmaceutical Classification Systems (BCS) class II drugs show poor solubility and high permeability in the body. Fenofibrate (FF) is a classic example of a BCS class II drug, used to treat high cholesterol and triglyceride (fat-like substances) levels in the blood. Atomic layer coating (ALC) is a surface engineering technology adapted from the semiconductor industry, where metal oxides are coated one atomic layer at a time over the active pharmaceutical ingredients (API) particles. ALC coating was proven to improve the processability, alter the hydrophilicity, improve the stability, and fine-tune the release of drugs. Herein, we report the intervention of ALC coating in enhancing the bioavailability of a poorly water-soluble drug (fenofibrate) in the animal model. The physical properties of uncoated fenofibrate were compared with those of zinc oxide-coated and silicon oxide-coated fenofibrate. Following the application of the coatings, the structural integrity (both chemical stability and solid-state stability) of the active pharmaceutical ingredient (API) remained uncompromised, as corroborated by 1H NMR and powder X-ray diffraction analyses. Notably, zinc oxide-coated fenofibrate exhibited favorable flow characteristics, whereas no discernible enhancement in flow behavior was observed for silicon oxide-coated fenofibrate. The results from contact angle measurements suggest that the silicon oxide-coated fenofibrate exhibits superior wetting behavior, as indicated by a contact angle nearing 0°. The application of ALC demonstrates an enhanced dissolution rate when compared to the uncoated active pharmaceutical ingredient (API) while leaving its equilibrium solubility unaffected. Coating the API with silicon oxide improves particle hydrophilicity and wetting properties, whereas zinc oxide coating aids in particle de-agglomeration, thereby enhancing their interaction with an aqueous medium. In vivo bioavailability studies conducted on rodents and larger animal (dog) models indicate a substantial increase in bioavailability (approximately 2 times) for the silicon oxide-coated API in comparison to the uncoated API, as determined by the area under the curve (AUC). Furthermore, the Cmax values for the silicon oxide-coated API also demonstrate a significant increase (approximately 3 times) over the uncoated API. Notably, an oral subacute toxicity study of ALC silicon-coated fenofibrate revealed no toxic effects attributable to the coating. This study underscores the potential of ALC in augmenting the bioavailability of BCS(II) drugs.

Ionic Liquid Assisted Green Synthesis of Quinoxaline Based Bisspirooxindoles: Anticancer Evaluation and Molecular Dynamics

AbstractIn this study, we have synthesized a series of novel quinoxaline based bisspirooxindoles through green protocol using ionic liquid [Bmim]BF4. All the compounds were well characterized by spectroscopic methods like FT‐IR, 1H NMR, 13C NMR, mass and finally the structures were authenticated by single crystal X‐ray diffraction (SCXRD) (4e). The target compounds were evaluated for their anticancer activity with different cancer cell lines like MDAMB‐231, MCF‐7, MCF‐10A, HCC‐1395, Molt‐4, and FaDU. The compounds 4d, 4g, 4m, and 4n showed 42.0%, 43.3%, 52.7%, and 56.0 percentage of growth inhibition respectively with the T cell acute lymphoblastic Molt‐4 cell line. The compounds 4b, 4c, 4 h, 4k, and 4m have shown 30%–39% of growth inhibition against FaDU cell line. Further, anticancer activity was validated with in silico molecular docking and molecular dynamics simulations. The outcomes of dynamics simulations exclusively emphasize that the compounds bind to HIS862 and TYR896 residues which are among the catalytic triad of PARP1. Finally, the results of ADME is also used to assess the drug likeness, which clearly shows that our target compounds are adaptable as potential drug pathways for medicinal chemists.

Design, synthesis of antipyrine-based Schiff bases and investigation of their cholinesterase and carbonic anhydrase activities by in vitro and in silico approaches

In this study, a series of antipyrine-based Schiff bases (1-10) was designed, synthesized, and evaluated as potential inhibitors of various metabolic enzymes, including acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and human erythrocyte carbonic anhydrase I and II (hCA I and hCA II). The target molecules were characterized by UV-Vis, FT-IR, 1H NMR, 13CNMR, LC-HRMS, and elemental analysis. All tested derivatives demonstrated low nanomolar inhibition with Ki values of in the range of 20.58 ± 0.35 to 53.11 ± 1.02 nM against AChE, 21.84 ± 0.40 to 54.41 ± 1.05 nM against BChE, 27.45 ± 0.41 to 48.22 ± 0.91 nM against cytosolic hCA I isoform associated with epilepsy, and 6.02 ± 0.11 to 29.32 ± 0.54 nM against cytosolic hCA II isoform associated with glaucoma. In general, most these molecules, except for a few, inhibited these enzymes more than acetazolamide (AZA) and neostigmine. Among them, compounds 5, 7, 8, and 9 showed the best inhibitory activities against AChE, BChE, hCA I, and hCA II, respectively. Docking results were calculated for the compounds that showed the best inhibitory activity against these enzymes and for reference compounds. Based on the molecular docking results, they were determined to have high binding energies, including hydrogen bonds, electrostatic interactions, and hydrophobic interactions. Absorption, distribution, metabolism, and excretion (ADME) parameters determined that all the synthesized pyrazolone ring-bearing Schif base derivatives (1-10) have the expected physicochemical properties in terms of drug-likeness and can be evaluated as orally active potential. Properties such as the electrophilicity index and chemical hardness were also investigated by density functional theory (DFT) at the B3LYP/6-311G** level of theory.

Design of toughed bio-based polylactide/polyamide 11 blends with regulatable size of dispersed phase and spherulites by interfacial stereocomplex crystallites

Enhancing the ductility of polylactide (PLA) through toughening modification to expand the application range of PLA aligns with the requirements of green development. In this study, eco-friendly bio-based plastic polyamide 11 (PA11) was chosen to modify poly(l-lactide) (PLLA). PA11 and poly(d-lactide) (PDLA) were grafted onto the main chain of ADR via simple reactive processing and utilized as reactive compatibilizers to improve toughening efficiency of PA11. The successful preparation of the graft copolymer was confirmed through 1H NMR, FT-IR and DSC, and a detailed investigation was conducted on how the composition and concentration of the compatibilizer influence the mechanical properties, phase morphology, crystallization, and nucleation behaviors of PLLA/PA11 blends. Elongation at break of the 5 % PDLA/PA11 graft copolymers toughed PLLA was as high as 222 % at 30 % PA11 content, which was 17 times greater than the PLLA toughened by pristine PA11 without compromising the strength. PLLA and PA11 were immiscible binary blends with PA11 droplet/PLLA matrix phase separated morphologies in the molten state. Based on the calculation of interfacial tension, the grafted copolymer would be mainly distributed at the interface between the two phases. The dispersion of PA11 droplet in PLLA matrix was improved since the interfacial interaction force was enhanced through in-situ reaction. The increase of the nucleation site and decrease of the spherulites size were worked synergistically by stereocomplex (SC) crystallites and PA11. Under the impact of reducing the size of the dispersed phase and spherulites, the toughness of blends was enhanced. This study provided valuable insights into the control of PLLA immiscible blend morphology and elucidated the relationship between the size of dispersed phase and spherulites and the ultimate mechanical performance of bio-based PLA materials.

Novel conjugated 5-pyridin-2-ylmethylidene 2-thio-4H-imidazol-4-ones and their complexes with copper(II) chloride

Three novel 2-thio-4H-imidazol-4-ones containing conjugated five, six- or seven-membered S,N-heterocycle and pyridin-2-ylmethylidene moiety (L) were synthesized by two-step reaction sequence starting from 2-thiohydantion. The ligand structures were confirmed by 1H NMR, 13C NMR and HRMS. The reactions of the ligands L with copper chloride dihydrate give the complexes of LCuCl2 composition. Copper coordination compounds with 6-(pyridin-2-ylmethylidene)-2,3-dihydroimidazo[2,1-b][1,3]thiazol-5(6H)-one (L1) and 2-(pyridin-2-ylmethylidene)-6,7-dihydro-5H-imidazo[2,1-b][1,3]thiazin-3(2H)-one (L2) were characterized by the X-ray data, demonstrating the distorted tetrahedral copper coordination environment. It was shown that the presence in the ligand L1 of a five-membered thiazolidine ring fused with imidazolone leads to a significant change in the geometric characteristics of the complex: an increase in the Cu-S distance and the flattening of copper coordination polyhedron. Both synthesized complexes were evaluated using cyclic voltammetry and demonstrated the quasi-reversible reduction of Cu(II) at ∼ −0.25 V. Testing of the antibacterial activity on the reporter strains E. coli ΔtolC pDualrep2 (AmpR) and E. coli lptDmut pDualrep2 (KanR) showed a lower activity of the synthesized copper-containing complexes compared to the complexes of similar ligand that did not have an additional condensed ring in its structure.

Effect of H2O2/ascorbic acid degradation and gradient ethanol precipitation on the physicochemical properties and biological activities of pectin polysaccharides from Satsuma Mandarin

In this work, three degraded polysaccharides (DMPP-40, DMPP-60, DMPP-80) were successfully obtained by H2O2/ascorbic acid degradation and gradient ethanol precipitation from Satsuma mandarin peel pectin (MPP), and their physicochemical properties, antioxidant and prebiotic activities were investigated. The molecular weight of MPP, DMPP-40, DMPP-60, DMPP-80 were determined to be 336.83 ± 10.57, 18.93 ± 0.54, 26.07 ± 0.83 and 8.71 ± 0.27 kDa, respectively. The ethanol concentration significantly affected the physicochemical properties of DMPPs. DMPP-60 showed the highest yield (69.07 %) and uronic acid content (64.85 %), DMPP-80 showed the lowest molecular weight (8.71 kDa), and the composition and proportion of monosaccharides of DMPPs were significantly different. Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H NMR) confirmed that DMPPs exhibited similar functional groups, while X-ray diffraction (XRD) indicated that DMPP-40 possessed some crystallographic sequences. Scanning electron microscopy (SEM) images directly verified the fragmented structure and reduced surface area of DMPPs. Besides, the H2O2/ascorbic acid treatment could obviously reduce the apparent viscosity and thermal stability of MPP. Meanwhile, the results of bioactivity assay showed that DMPPs possessed better antioxidant activity and probiotics pro-proliferative effects compared with MPP. DMPP-80 could significantly inhibit lipopolysaccharides (LPS)-stimulated production of inflammatory factors (including nitric oxide (NO), interleukin (IL)-6, tumor necrosis factor (TNF)-α and interleukin (IL)-1β) in RAW264.7 cells. Results suggest that the H2O2/ascorbic acid combined with gradient ethanol precipitation has potential applications in degradation and separation of MPP to improve its biological activities.

The new metal-free, zinc, magnesium, indium ball-type phthalocyanines and their hybrids with graphene oxide: Synthesis, investigation of photophysical, photochemical properties and theoretical studies

In this study, four ball-type phthalocyanines (BTPc-H2-4, BTPc-Zn-5, BTPc-Mg-6, BTPc-In-7) were synthesized from 3,3,′((3,5-di-tert-butyl-1,2-phenylene)bis(oxy)diphthalonitrile in a single reaction step. Non-covalent ball-type phthalocyanine (BTPc)-graphene oxide (GO) hybrids (BTPc-GO) were prepared by simple sonication method. The structures were confirmed by elemental analysis, ultraviolet–visible (UV–Vis), fourier-transform infrared (FT-IR), proton nuclear magnetic resonance (1H NMR), MALDI-TOF MS spectroscopies, elemental analysis and scanning electron microscope (SEM). The photophysical and photochemical properties of ball-type phthalocyanines were investigated in dimethyl sulfoxide (DMSO) and tetrahydrofuran (THF). In this way, the contribution of solution polarity to these properties was compared. The contribution of GO was examined by examining the singlet oxygen quantum yields of BTPc-GO hybrids in DMSO. In addition, the structural properties of ball-type phthalocyanines were examined through theoretical studies and the effect of structural properties on experimentally determined band gaps was examined. Interestingly, we also report that ball-type thalocyanines are both photostable and exhibit extremely high singlet oxygen quantum yields. In addition, we can state that hybrids of these compounds with GO also show the ability to increase the singlet oxygen quantum yield, depending on the degree of interaction.

Synthesis, crystal structures and antiproliferative activities of a new indole-containing dipyridylmethanone hydrazone Schiff base and its cadmium(II) complex.

In this study, we introduce a novel indole-containing pyridine-based Schiff base, (E)-2-({[bis(pyridin-2-yl)methylidene]hydrazin-1-ylidene}methyl)-1H-indole, C20H15N5 (2-DPHI), and its cadmium(II) complex poly[[2-({[bis(pyridin-2-yl)methylidene]hydrazin-1-ylidene}methyl)-1H-indole]di-μ-chlorido-cadmium(II)], [CdCl2(C20H15N5)]n (pCd2), as potential anticancer agents. The Schiff base was synthesized by reacting dipyridylmethanone hydrazone with indole-2-formaldehyde, while the cadmium complex was prepared by combining CdCl2 and 2-DPHI in methanol at room temperature. Both compounds were evaluated for their cytotoxicity against three human cancer cell lines (A375, A549 and HeLa) and a normal cell line (HFF-1). The ligand 2-DPHI exhibited notable antitumour activity, with an IC50 value of 12.22 µM against A375 and 15.17 µM against A549 after 48 h, while the pCd2 complex showed an even stronger inhibition of A375 cells, with an IC50 value of 4.88 µM, outperforming both 2-DPHI and CdCl2. Both compounds demonstrated lower toxicity towards normal cells compared to cancer cells. The structures of 2-DPHI and pCd2 were fully characterized using single-crystal X-ray diffraction, elemental analysis, high-resolution mass spectrometry and FT-IR, 1H NMR, 13C NMR and UV-Vis spectroscopy.

Supramolecular Polymerization of Pseudo[2]rotaxanes Formation of per‐Imidazole Pillar[5]arene‐based Host–Guest Complexations and Halogen Bonding Interactions

AbstractIn this study, we reported the construction of 3D supramolecular polymeric networks using per‐imidazole pillar[5]arene (DIMP5) as a host and 1,4‐diiodotetrafluorobenzene (L) as a halogen bond donor in chloroform. The supramolecular polymerization process was characterized by 1H NMR, 19F NMR spectroscopy, and X‐ray single crystal analysis. The C─I⋯N distance (2.78 Å) and C─I⋯N angle (177°) clearly indicated the formation of halogen bonds in the crystal structure. Meanwhile, by introducing adiponitrile (G) as the guest, a supramolecular polymerization of pseudo[2]rotaxanes was also prepared, which was driven by DIMP5‐based host–guest complexations and halogen bonding interactions.

C18‐DABCO‐AA: A Novel Brønsted Acidic Gemini Surfactant for the Environmental Benign Synthesis of 2,3‑Dihydroquinazolin‑4(1H)‑ones in Water at Ambient Temperature

AbstractWe have successfully synthesized a new acidic surfactant named C18‐DABCO‐AA, which contains octadecyl and acetic acid substituent on DABCO (1,4‐diazabicyclo [2.2.2] octane) unit, with an excellent yield. The synthesized surfactant was analyzed using FT‐IR, 1H NMR, and 13C NMR spectroscopic techniques. Its thermal behavior was analyzed by using the TGA–DTA technique. Our analysis indicates that the synthesized surfactant has excellent surfactant properties. Its critical micelle concentration (CMC) is 0.80 mM as determined by the conductivity method and UV–vis absorption measurement at 298.15 K. Surfactant also showed strong acidic properties with a pKa of 3.3. It is the best catalyst for the synthesis of 2,3‑dihydroquinazolin‑4(1H)‐ones (DHQs) in water at 40 °C. The synthesis is achieved via two‐component reactions of various aromatic aldehydes and anthranilamide in water at a CMC concentration of C18‐DABCO‐AA. The method was also extended for synthesizing DHQs via two‐component reactions of different ketones and anthranilamide under similar reaction conditions. The products were achieved in with yields ranging from good to excellent within 60–90 min. Additionally, the aqueous solution with C18‐DABCO‐AA was reused up to five times with a minor decrease in product yield. The present protocol is fast, energy‐efficient, and can be used on a large scale for synthetic purposes. Additionally, it boasts impressive environmentally friendly credentials.

Highly selective and sensitive N-amidothiourea-based fluorescence chemosensor for detecting Zn2+ ions and cell Imaging: Potential applications for plasma membrane detection

A “turn-on” fluorescent sensor L was developed for the selective detection of Zn2+ ions in biological settings. This sensor exhibited a specific response to Zn2+ ions, with a detection limit of 39 nM. Analyses through titration and Job’s plot confirmed that the formed complex has a 2:1 stoichiometry (L: Zn2+). The sensor displayed strong selectivity for Zn2+ over other metal ions, demonstrating a robust binding affinity while effectively reducing interference from heavy metals. The identification process was validated by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR) titrations, mass spectrometry (MS), and Density Functional Theory (DFT) calculations. Maximum fluorescence intensity was achieved upon interaction with Zn2+ ions within a physiological pH range of 7.0–7.5. Moreover, successful imaging experiments in HEK293 cells highlighted the sensor’s potential as a powerful tool for monitoring interactions at the plasma membrane.

Benchtop NMR spectroscopy for quantitative determination of milk fat and qualitative determination of lactose: From calibration curve to deep learning

This study compares three different methodologies for the quantification of the fat content of ultra-high temperature (UHT) milk using benchtop proton nuclear magnetic resonance (1H NMR) spectroscopy, a flagship of green, accessible, and state-of-the-art technology suitable for modern laboratory environments. The evaluated approaches included traditional calibration curve and machine learning algorithms, with emphasis on partial least squares regression (PLS-R) and artificial neural networks (ANN), to estimate the fat content in skimmed, semi-skimmed and whole milk. Among these, ANN provided the most accurate results for all types of milk, particularly in skimmed milk, with a relative standard deviation (RSD) of 14.9% and an accuracy of −7.3%. The calibration curve showed higher variability, with an RSD of 34.1% and trueness of 25.3% for skimmed milk. PLS-R improved accuracy in relation to the calibration curve approach, reducing RSD to 18.9% and trueness to −17.7%. The developed method has been successfully applied to determine the fat content in 51 samples of UHT milk purchased in different Spanish supermarkets, providing adequate results for each of the three categories considered, including goat's milk, sheep's milk, and milk coffee. Furthermore, the application of machine learning has proven its validity by successfully distinguishing between lactose and lactose-free UHT milk.

Isolation of Natural Veratrylidenehydrazide Compound from Wedelia Biflora and Synthesis of Veratrylidenehydrazide Analogue: Investigation of Larvicidal Activity Against Culex Quinquefasciatus and Toxicity Analysis in Nontarget Aquatic Species

AbstractIn this study, veratrylidenehydrazide was isolated from Wedelia biflora, and compounds (1a, 2a, and 3a–j) were synthesised to evaluate their larvicidal and antifeedant activities. Veratrylidenehydrazide 1a was verified using GC‐MS. The veratrylidenehydrazide analogues 2a and 3a–j were synthesised via a condensation method with yield range 71%–92%. The compounds (1a, 2a, and 3a–j) were synthesised and characterised through FT–IR, 1H NMR, 13C NMR, mass spectrometry, and elemental analysis. Veratrylidenehydrazide 1a was verified using GC‐MS analysis. Natural veratrylidenehydrazide compound 1a and the synthesised veratrylidenehydrazide analogues (2a, 3a–j) were screened for larvicidal activity against Culex quinquefasciatus. The larvicidal activity of compound 3g was found to be highly active, while low toxicity was observed against Oreochromis mossambicus nontarget aquatic species compared to natural veratrylidenehydrazide. Compound 3g exhibited a higher binding affinity (−8.8 kcal/mol) compared to standard of temephos (−4.5 kcal/mol), equipotential binding affinity against permethrin (−9.1 kcal/mol), and diflubenzuron (−8.5 kcal/mol). Lead molecules have larvicidal properties, and their use as insecticides makes them important.

Preparation of N-(2-hydroxypropyltrimonium chloride)-O-dodecylylpyridine chitosan quaternary ammonium salt and its antibacterial activities

Chitosan derivatives, including O-carboxymethyl chitosan (CMC), N-(2-hydroxypropyltrimonium chloride)-O-carboxymethyl chitosan (QCMC), and N-(2-hydroxypropyltrimonium chloride)-O-dodecylylpyridine chitosan quaternary ammonium salt (DQCMC), were synthesized and characterized using Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (1H NMR) spectroscopy, Ultraviolet-visible (UV-vis) spectroscopy, and element analysis (EA). The antibacterial activities of chitosan and chitosan derivatives against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were evaluated through the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and antibacterial rate assays. Results demonstrated that DQCMC exhibited significantly higher antibacterial efficacy compared to chitosan, CMC, and QCMC. The MIC of DQCMC against E. coli and S. aureus were 31 μg/mL and 7 μg/mL, respectively, with a 100% antibacterial rate at a concentration of 0.5 mg/mL. Furthermore, assessment of mouse fibroblast (L929) cell viability using cell counting kit-8 (CCK-8) methods revealed no toxicity associated with the material.

Exploring unique fluorescence characteristics of novel star-shaped molecules containing NBD fluorophores via different linkages: Distinct results with an aromatic ether linkage

This paper presents a novel design of three star-shaped molecules linked with 4-chloro-7-nitrobenzofurazan (NBD-Cl), highlighting their unique properties for fluorescence applications. NBD-Cl is a substance that is non-fluorescent until it is bound to different functional groups. The three molecules in the shape of a star were created by connecting various equivalents of NBD-Cl to three different cores. The three molecules are referred to as S-1 (NBD-SR), S-2 (NBD-NHAr), and S-3 (NBD-OAr), which are based on thioether, amine, and ether cores, respectively. In addition, a fourth compound A was studied, where A is a single linear branch which is a precursor to S-3. The chemical structure and physical and spectroscopic properties of these molecules were studied and characterized using 1H NMR, 13C NMR, and IR spectroscopy. UV–visible and luminescence spectrometry techniques were used to explore the unique electronic characteristics of all of the molecules using solvents of differing polarity. The star-shaped molecule S-1 showed a distinct, blue-shifted UV–vis absorption spectrum compared to NBD-Cl and the other compounds, with a wavelength range between 410 and 415 nm. Meanwhile, its emission peaks were like those of the other compounds, falling between 530 and 545 nm. This molecule exhibited the highest Stokes shift, ranging between 110 and 137 nm in different solvents, which is higher than the other molecules being studied. The Stokes shift values for compounds A, S-2, and S-3 range between 60 and 100 nm and the spectra display a red-shifted UV–vis absorption spectrum compared to that of S-1. This study reveals that the fluorescence emission wavelength of S-2 (NBD-NHAr) is the longest among the fluorescence emissions. Interestingly, the fluorescence emission of compounds A and S-3 (NBD-OAr) was unexpectedly higher than S-1, though still lower than S-2. This outcome was surprising as it deviates from previous reports, which indicated that NBD-OR derivatives generally lack significant fluorescence. The observed fluorescence enhancement in compounds A and S-3 suggests a unique interaction between the NBD moiety and the aromatic group, possibly due to electronic effects or structural configuration, leading to a more efficient fluorescence pathway. Additionally, there was a noticeable decrease in relative fluorescence as the solvent’s dielectric constant increased, accompanied by a redshift, with slight deviations in the pattern for some molecules.

Synthesis, crystal structures, DFT calculations, and oxygen radical absorbance capacity of 5-arylidene-thiazolidine-2,4-dione derivatives

A new green methodology has been developed for the synthesis of a series of substituted 5-arylidene-2,4-thiazolidinediones (ATZDs) 3a-q through Knoevenagel condensation, using barium hydroxide as an efficient heterogeneous catalyst. All compounds were characterized by ¹H NMR, ¹³C NMR, and HRMS spectroscopy. Additionally, seven compounds were analyzed by X-ray diffraction (XRD). Furthermore, some selected TZD derivatives were screened for their antioxidant activity using oxygen radical absorbance capacity (ORAC) assays. The results showed that five compounds exhibited excellent antioxidant properties, with ORAC values ranging from 4.73 TE to 6.31 TE, surpassing the reference antioxidants ferulic acid (3.70 TE) and melatonin (2.45 TE). Computational investigations based on the DFT method revealed that these compounds exert their antioxidant activity primarily through the HAT mechanism, preferentially from the OH bond rather than the NH bond. This study highlights the advantages of this methodology, providing products of high purity, with good yields and short reaction times, and proposes 5-arylidene-thiazolidine-2,4-dione derivatives as promising antioxidants.

Synthesis, Characterisation, Single Crystal Structure and Evaluation of a Redox Innocent Carbazate Functionalized Phenanthroline for Antimycobacterial and Anticancer Activity

Development of bioactive candidates for cancer and bacterial infections are ever demanding challenges due to the resistance shown by these cancer and bacterial cells for already exposed drug molecules. Methyl carbazate derivatized phenanthroline compound 6-[2-(methoxycarbonyl)diazen-1-yl]-1,10-phenanthroline-5-one (MCDPO) is synthesized in a three step reaction from 1,10-phenanthroline. The spectroscopic features of MCDPO are studied by HRMS, IR, 1H NMR and 13C NMR, UV-visible spectroscopy. The three-dimensional molecular structure of the MCDPO is confirmed by single crystal XRD study. The MCDPO crystallized in a triclinic system P-1 space group with the following unit cell parameter: a=5.0347(2) Å, b=10.3509(4) Å, c=11.8816(4) Å, α=84.431(3)°, β=84.172(3)°, γ=81.380(4)°, and V=606.92(4) Å3 at T=133 K. The MCDPO is containing aromatic rings, hydrogen bonding donors as well as hydrogen bonding acceptor groups forming supramolecular molecular arrangements through C-H···O, C-H···N, C-O···C, π-π and π···C non-covalent interactions. Electrochemical redox and electrochromic features of MCDPO are studied through cyclic voltammetry and UV-vis based spectroelectrochemistry. This compound shows good anticancer activity with IC50 values 1.438, 6.576 and 2.901 µM against 4T1, MCF-7 and PC-3 cancer cell lines respectively. The flow cytometry study on 4T1 cells suggests that the MCDPO promoted cancer cell death by inducing apoptosis, and cell cycle arrest in the G0/G1 phase. It also induces nuclear fragmentation and reactive oxygen species (ROS) generation, which was studied by DAPI, AO, and DCFH-DA based cellular staining studies by fluorescence confocal imaging. The MCDPO also studied for antibacterial activity against Escherichia Coil bacteria and Mycobacterium tuberculosis (Mtb). The MCDPO shows minimum inhibitory concentration (MIC) of 0.39 µg/mL against Mtb which is slightly better than the one of the clinically used drug candidates Ethambutol.